PROPERTY, PLANT AND EQUIPMENT, INTANGIBLE ASSETS AND GOODWILL

Property, Plant and Equipment

The Company’s property, plant and equipment consisted of the following classes of assets as of March 31, 2019 and December 31, 2018, respectively:



(In thousands)	March 31, 2019		December 31, 2018
Land, buildings and improvements	$	572,362	$	572,904
Structures	2,833,051		2,835,411
Towers, transmitters and studio equipment	366,500		365,991
Furniture and other equipment	818,278		793,756
Construction in progress	112,442		116,839
	4,702,633		4,684,901
Less: accumulated depreciation	2,961,395		2,893,761
Property, plant and equipment, net	$	1,741,238	$	1,791,140

Indefinite-lived Intangible Assets

The Company’s indefinite-lived intangible assets consist of Federal Communications Commission (“FCC”) broadcast licenses in its iHM segment and billboard permits in its Americas outdoor advertising segment. Due to significant differences in both business practices and regulations, billboards in the International outdoor segment are subject to long-term, finite contracts unlike the Company’s permits in the United States. Accordingly, there are no indefinite-lived intangible assets in the International outdoor segment.

The Company performs its annual impairment test on goodwill and indefinite-lived intangible assets, including Federal Communication Commission ("FCC") licenses, as of July 1 of each year. In addition, the Company tests for impairment of intangible assets whenever events and circumstances indicate that such assets might be impaired. During the three months ended March 31, 2019, the Company recognized non-cash impairment charges of $91.4 million in relation to indefinite-lived FCC licenses as a result of an increase in the Company's weighted average cost of capital.

Other Intangible Assets

Other intangible assets include definite-lived intangible assets and permanent easements. The Company’s definite-lived intangible assets primarily include transit and street furniture contracts, talent and representation contracts, customer and advertiser relationships, and site leases and other contractual rights, all of which are amortized over the shorter of either the respective lives of the agreements or over the period of time the assets are expected to contribute directly or indirectly to the Company’s future cash flows. Permanent easements are indefinite-lived intangible assets which include certain rights to use real property not owned by the Company. The Company periodically reviews the appropriateness of the amortization periods related to its definite-lived intangible assets. These assets are recorded at amortized cost.

The following table presents the gross carrying amount and accumulated amortization for each major class of other intangible assets as of March 31, 2019 and December 31, 2018, respectively:



(In thousands)	March 31, 2019					December 31, 2018
	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Transit, street furniture and other outdoor contractual rights	$	528,232	$	(443,963	)	$	528,185	$	(440,228	)
Customer / advertiser relationships	1,237,115		(1,210,498		)	1,249,128		(1,208,056		)
Talent contracts	164,932		(150,289		)	164,933		(148,578		)
Representation contracts	77,508		(72,419		)	77,508		(70,829		)
Permanent easements	163,341		—			163,317		—
Other	394,923		(249,018		)	382,897		(244,993		)
Total	$	2,566,051	$	(2,126,187	)	$	2,565,968	$	(2,112,684	)

Total amortization expense related to definite-lived intangible assets for the three months ended March 31, 2019 and 2018 was $13.9 million and $47.0 million, respectively.

As acquisitions and dispositions occur in the future, amortization expense may vary. The following table presents the Company’s estimate of amortization expense for each of the five succeeding fiscal years for definite-lived intangible assets:



(In thousands)
2020	$	43,788
2021	38,457
2022	32,707
2023	24,849
2024	20,983

Goodwill

The following table presents the changes in the carrying amount of goodwill in each of the Company’s reportable segments:



(In thousands)	iHM			Americas Outdoor		International Outdoor			Other		Consolidated
Balance as of December 31, 2017	$	3,255,208		$	507,819	$	206,224		$	81,831	$	4,051,082
Acquisitions	77,320			—		—			—		77,320
Dispositions	(1,606		)	—		—			—		(1,606		)
Foreign currency	—			—		(8,040		)	—		(8,040		)
Balance as of December 31, 2018	$	3,330,922		$	507,819	$	198,184		$	81,831	$	4,118,756
Acquisitions	2,767			—		—			—		2,767
Foreign currency	(27		)	—		(3,184		)	—		(3,211		)
Balance as of March 31, 2019	$	3,333,662		$	507,819	$	195,000		$	81,831	$	4,118,312